Crystal Structure of the Molecular Complex of Silicon Tetrafluoride with 4-Phenylpyridine.

The crystal structure of the silicon tetrafluoride molecular complex with 4-phenylpyridine SiF4·2ppy has been determined by X-ray diffraction analysis. Although 4-phenylpyridine has a higher proton affinity than pyridine, the Si–N bond length in crystalline SiF4·2Py is shorter by 0.03(2) Å than in SiF4·2ppy. The energies of donor-acceptor Si–N bonds in SiF4·2Py (220.6 kJ/mol) and SiF4·2ppy (225.0 kJ/mol) calculated by the M06-2X/def2-TZVP method agree with a slightly higher proton affinity of 4-phenylpyridine. [ABSTRACT FROM AUTHOR]